Dormant Oil

Dormant Oil is not a poison. It acts as a suffocant, smothering bugs, eggs, and spores. As such, it does not eradicate bugs. It works to control them, at least the first generation. While it can be a chemical of sorts if it is petroleum based, vegetable-based oil works just as well and are completely organic.

  • Use on any trees, shrubs, or plants where you are currently or have previously had issues with aphids, scale, coddling moth, psyllids, or mites. It also works to smother spores of powdery mildew.
  • Use between 40º and 75º. Since it is just oil, below 40º it gels and above 75º it can burn.
  • Use as often as you’d like within the above noted temperature band.
    • When trying to control coddling moth on Apple and Pear trees, you can spray as often as you want but it is best sprayed when the pedals are dropping.

The Recipe:

  • In a 32 oz spray bottle use
    • One shot glass full of vegetable oil,
    • A few drops of dish soap (the helps the oil stick and not run off),
    • Fill the rest of the bottle with water.
  • In a 1-gallon sprayer use
    • A cup of vegetable oil,
    • A teaspoon of dish soap,
    • Fill the rest of the sprayer with water.

It’s just oil. It doesn’t hurt anything or anyone. It can give a brown tint to blue things like Blue Spruce or blue varieties of Juniper, but it doesn’t cause any long-term damage.